Saliva is the principle protective agent for the mouth and thus is of primary importance to oral health maintenance. Perturbations of salivary secretory mechanisms can consequently lead to serious oral health problems. The objective of this project is to study the membrane and cellular processes which underlie the phenomenon of salivary fluid secretion and thus to contribute to our understanding of the fluid secretory process in normal and diseased states. Because similar secretory mechanisms are thought to be common to a number of other exocrine glands, this information should be of rather broad applicability and interest. During the present reporting period our specific areas of focus were the following. (1) Studies of the regulation of the rat parotid acinar Na-K-2Cl cotransporter by secretagogues and other stimuli were continued. (2) A polyclonal antibody against the rabbit parotid Na-K-2Cl cotransport protein was prepared and used to identify possible positive clones from a rabbit parotid cDNA library. (3) Investigations of the functional properties of salivary ducts were continued. In particular, the properties of an amiloride-sensitive sodium channel were characterized. (4) The effects of various attachment factors on the adhesion and spreading of the human salivary ductal cell line HSY were evaluated.